In today's complex Internet environment, traffic flow data packets (packets) are processed through routing systems (routers) without regard to the type of data they represent. This approach is referred to as “Best Effort” service. However, with the advent of digitized multimedia content, including voice and other signal types, there is a growing need to process packets according to specific routing requirements associated with each data packet.
Quality of service (QoS) is the forwarding priority processing of signal types through a routing system. The aim of QoS is to provide multiple distinct classes of service where each service class matches network performance requirements of the packet. For example, voice calls require a particular QoS service class that guarantees low latency, the time required to locate the first bit or character in a storage location. Low latency ensures that packets received by a router are forwarded within a certain minimum set of time requirements. For example, if a router receives a non-voice packet and a voice packet at roughly the same time, the voice packet should be given higher priority and forwarded through the router as quickly as possible to ensure timely end-to-end delivery. There are other types of multimedia signals that are not delay sensitive, but may be bandwidth sensitive. These signal types require bandwidth guarantees throughout the network to accommodate a particular traffic type.
Certain types of traffic do not require low latency guarantees, but do require an increased amount of bandwidth to route larger amounts of signal data. Particular bandwidth guarantees must exist throughout the network to accommodate certain types of traffic, e.g., bulk data traffic. Conventional network topologies process data signals indiscriminately. That is, voice signal packets are processed with the same forwarding priority as data signal packets. This technique does not effectively evaluate and identify signals based on customer service level agreements (SLAs). The concept of Differentiated Services (DiffServ) was developed by the Internet engineering community to formalize an architecture for providing guaranteed service to aggregate service classes. Nevertheless there remains a need in the art for a way to provide hardware to efficiently implement Differentiated Services in a multimedia network routing system.
U.S. Pat. No. 6,091,709, “Quality of Service Management for Packet Switched Networks,” assigned to International Business Machines Corporation (Armonk, N.Y.), describes a packet router for a data packet transmission network, the router is described as offering priority services of the type required for isochronous handling of data representing real-time voice, and includes a Quality of Service (QoS) management system for ensuring that guarantees associated with such priority service can be met with a high degree of certainty. This management system is stated to provide prioritized queues, including a highest priority queue supporting reservations for the priority service suited to isochronous handling. The highest priority queue and other queues are closely monitored by a QoS manager element for states of near congestion and critical congestion. When neither state exists, filler packet flows are promoted from lower priority queues to the highest priority queue in order to keep the latter queue optimally utilized. If all lower priority queues are empty at such times, dummy packets are inserted as filler flows. Dummy packets have a form causing routers and other stations receiving them to immediately discard them. The volume of dummy traffic allowed for each queue of the system is a predetermined fraction of the queue's estimated peak traffic load, and that volume is displaceable to allow forwarding of additional traffic through the queue when conditions require it. When a state of near congestion exists, the QoS manager demotes filler flow units from the highest priority queues to lower priority queues, in order to lessen the potential forwarding delays presented to real traffic occupying the highest priority queue. When a state of critical congestion exists in the highest priority queue, admission of new incoming traffic flows to that queue is suspended and forwarding of filler flows from that queue out to the network is also suspended.
U.S. Pat. No. 6,075,791, “System for Guaranteeing Data Transfer Rates and Delays in Packet Networks,” assigned to Lucent Technologies Inc. (Murray Hill, N.J.), describes a system which services a plurality of queues associated with respective data connections. The system is described as guaranteeing data transfer rates and data transfer delays to the data connections. This is achieved by associating each connection having at least one data packet waiting in its associated queue (such a connection called a backlogged connection) with a timestamp generated as a function of system parameters including (a) the number of queues that are backlogged, (b) the data transfer rate guaranteed to each connection, (c) the sum of data transfer rates guaranteed to all backlogged connections, (d) the previous timestamp of the connection, and (e) the weighted sum of the timestamps of all backlogged connections, each timestamp weighted by the data transfer rate guaranteed to the corresponding connection. The backlogged connection associated with the timestamp having the smallest value among all of the backlogged connections is then identified and a data packet is transmitted from the queue corresponding to that connection. A new timestamp is then generated for that connection if it is still backlogged. Once the transmission of the data packet is completed, the foregoing determination of the connection with the minimum timestamp is then repeated to identify the next queue to be serviced.
U.S. Pat. No. 5,946,311, “Method for Allowing More Efficient Communication in an Environment Wherein Multiple Protocols are Utilized,” assigned to International Business Machines Corporation (Armonk, N.Y.), describes a method and system that allow one or more network protocol emulators, composed of one or more network protocol emulation controllers and one or more network protocol emulation entities, which are overlaid onto the one or more base networks utilizing different communications protocols for the purpose of allowing said one or more networks to be accessed and utilized as if the one or more networks were utilizing protocols emulated by the one or more network protocol emulators. The method and system are described as using the following steps: (1) Apprising the one or more network protocol emulation controllers of network capability information inherent within protocols utilized by the one or more networks onto which the one or more network protocol emulation controllers are overlaid; (2) directing that the one or more network emulation controllers utilize the one or more network capability information of which they have been apprised to define communication capabilities for certain network protocol emulation entities within the control of the one or more network protocol emulation controllers; and (3) directing either the one or more network protocol emulation controllers or the one or more certain network protocol emulation entities within the control of the network protocol emulation controllers to utilize such defined communications capabilities to ensure that the network protocol emulation entities do not request a communications link to one or more other network protocol emulation entities that substantially exceeds the defined communication capabilities of the one or more other network protocol emulation entities.